Method of preparing pulp



-- weight may be added to the mass, and paper tartan 's'ra'ras Paranaerr es.

cam. AoHE-WIIG. or PORTLAND, MAINE.

METHOD DEPREPARING PULP.

No hrawing.

This invention relates to the production oi pulp from cellulosicmaterials, including pine wood, white pine, Norway pine, and other woodswhich are rich in resinous sub stances, including turpentine, all ofwhich" substances are herein expressly intended to be included in thegeneral term, ligne'ous matter.

In my application #231,204, filed April 27th, 1918, a methodof-preparing pulp is described whereby the ligneous matter for the mostpart is retained in order that its suitable for newsprint may beproduced.

The method involves two treatments,

which are carried on successively. I

By the first treatmentthe' cellulosic material, composing the pulp issoftened, that is to say, the ligneous matter is softened but notdestroyed and the fibers are swollen and caused to separate.

By the second treatment the treated mass is cooked with a bisulfite pulpforming liq-'- u'or for a relatively shortperiod of time, the processbeing checked before the destruction of the ligneous matter occurs.

A solution of sodium chlorid, NaC-l, is employed, in the firsttreatment, and I find that this substance doesnot discolor the fiber buttends to whiten it. and when the treated mass is cooked with thebisullite pulp forming liquor thefibcr is not discolored and anunbleached pulp is produced which is suit-- able for newsprint paper butwhich may be bleached if desired for the finer grades. of paper.

The present invention is an improvement on the aforesaid method and hasfor its ob ject the production of unbleached pulp by a novel methodinvolving the employment of a bisulfite pulp forming liquor or; in otherwords the sulfite process, whereiinthe lig-. neous matter is removedfrom the. fiber or substantially so, as contrasted to being saved andused as a. constituent of the pulp.

13y my present method a high grade of unbleached pulp may be made ofhighgrade cellulosic materials and a good unbleached pulp made of the lowgrades of cellulosic materials, such as the pinesabdve noted,

Specification of Letters Patent.

which is suitable for newsprint paper, which can not be made by themethod of my said application.

My present invention involves two treatments which I have carried onsuccessively, similar to the method of the aforesaid appli- 'ation,although the object sought to be attained is the destruction and removalof the ligneous matter. v The two successive treatment-sale or may becarried on at their maximum tempera,- tures and forlong periods of time,and particularly the first treatment Where the period of time iscontinued for a'great many hours and until the ultimate result has beenobtained.

In carrying out my first treatment, I may proceed as follows Thematerial or substance employed, in small pieces or chips, is placed in atank or digester, which may be opened or closed,

' and. a softening agent, as a solution of sodium chlorid NaCl, isadded,as for instance,

Patented Jan. 6,1920.

Application filed. February 20,1919. Serial no. 2 78257.

I may add water containing from one-half of one to e per cent. of sodiumchlorid, and

then heat the mass to a temperature from 70 C. to 110 Cmfor from 12 toT2 hours, the temperature and the time being more or less variabledepending upon the material used and the strength thereof, yet' it willbe understood that ordinarily the higher the temperature the shorter thetime required and vice versa. I

During this first treatment the lign'eous' matter is variously affectedand in different degrees, as for instance the dissolutionof some of thel gfnenes 1s hastened and of others is retarded; the vaporization ofsome of the lignencs is also hastened and of others is retarded; thesoftening of some of the lignenes is hastened and of others is retarded;and probably all are more or less prepared for reaction with thebisulfite pulp forming liquor-which is employed-in thesubsequenttreatment.

' The cellulosicpieces or chips are saturated with the softeningsolution which is further utilized in the performance of ,the secondtreatment of the method. a

This solution is then drawn oft or removed.

The same solution may be used repeatedly I asa softening agent for,alarge number of times, 1f desired".

As anexaing e of the first treatment in case of thepm s above noted,some of the resinous substances are dissolved in the solution and otherssoftened. and those of a volatilecharacter, such as turpentine arevapoi-med, and may be collected, if desired, and

all which remain are more /or less affected,

so that they'are better preparedfor reactio duringthe second treatment.The second treatment.-The mass having been thus treated is, then cookedwith a bisulfite pulp forming agent, or a sodium chlo'rid solutiondepending upon that kind of paper the pulp is to be used, for instance,if during the'first treatment a sodium chlorid solution is employed thenduring the second treatment a bis'ulfite liquor will be employed and anunbleached pulp suitable .for newsprint paper (will be produced, or iuaybe" bleached. for the finer grades of a er. A,

p he strength of the bisulfite solution may '20, be such together withthe time and temperature' of cooking that the ligneous matter maypractically be removed from the fiber.

The second treatment may continue for a period of time, say, from 10 to24 hours at 25 temperature of from lIOdegre'es C. to 135 degrees C, butthe longer the period of time and, the lowerthe temperature within reasonable limits'the better the pulp.

, A reaction takes place between the sodium chlorid with which the massis saturated and the bisulfite liquor employed during .the secondtreatment to which I attribute "at least in part some of. the advantagesgained by this process.

I claim i 1. The method of preparing cellulosi -material which consistsintreating the material withksodium chlorid and subsequently cooking themass with a 40 bisulfite pulp forming liquor until substan? tially allthe ligneous matter hasbeen freed from the fiber. 1

'2. The method of preparing pulp from cellulosic material which consistsin two successive treatments, first, treating the' material with asodium chlorid solution, and

second in cookin the treated mass with a bisulfite pulp forming liquoruntil substantially all ligneous matter has been .freed 60 from thefiber.

3. The method of preparing pulp from cellulosic material in' the form.of chips,

I which consists in adding a solution of sodium chlorid to the material,heating the mass for a period of time to dissolve some of the ligneousmatter in the solution, and "aporize some and prepare the remainder forsubsequent reactioin'then drawing off the solutionand then cooking thetreated mass. 'with a bisulfite pulp forming liquor until substantiallyall-of theligneous matter is freed from the fiber.

' 4. The method of "preparing pulp from cellulosic material in the formof chips, which. consists in adding a solution of sopulp from I diumchlorid to the material, heating the mass for a period of time to softenthe ligneous matter, and dissolve some in. the solution and preparesomefor subsequent reae; tion, then drawing off the solution and thencooking the treated mass witha 'bisulfite pulp forming liquor untilsubstantially all of) the ligneous matter is freed from the fi er.

5, The method of preparing pulp from cellulosie material in 'the form ofchips, which consists in adding a solution of sodium chlorid to thematerial, heating the mass for a period of time to soften the [ligneousmatter and dissolve some in the solution and vaporize some, and preparesome for subsequent reaction, then drawing oil the solution, and thencooking the treated mass with a bisulfite pulp forming liquor untilsubstantially all of the ligneous matter is 8 5 freed from'the' fiber. Iv I 6. The method of preparing pulp from I cellulosic material in theform of chips, which consists in adding a solution of sodium 'chloridto. the material, heating the mass for a period of time to soften theligneous matter and dissolve some in the solutiou, and prepare some forsubsequent re-' action, then drawing oil the solution, and then cookingthe treated mass with a-bisuhv fite pulp forming liquor until some ofthe ligneous. matter has 'been dissolved by the liquor and substantiallyall is freed from the fiber.

7. The method of preparing pulp from cellulosic materialin the formot'chips.' which consists in adding a solution of so-, dium chlorid tothe :material, heating the mass for a period of timeto softenthe'ligneous matter and dissolve some, in thesolu tion, and prepare somefor subsequent ,reaction, then drawing off the solution, and thencooking the treated mass with bisulfite pulp forming liquor until someof the ligneous matter tially all is free'dfrom the filier.

8. The method'of preparing pulp from cellulosie material, which consistsin treating the material in the form of chips with a Water solution ofsodium chlorid for a period of time and at a temperature, substantiallyas specified, and subsequently cooking the mass with a bisulfite pulpforming liquor for a period of time and at a tenor-V perature,substantially as specified, whereby substantially all ligneous matter isfreed from the fiber. v

In testimony whereof, I have signed my name to this specification,inlthe presence of two subscribing witnesses;

, GAR-L BAGHELWIIG. lVitnesses *Cnsnnns M. DRUMMOND, W'ADLEIGH'B. DnoMonn.

has been dissolved by the 116- liquor, some has been vaporized andsubstan

